1. Related Technical Fields
Related technical fields include control devices, control methods of a control device, and computer programs which change various types of control values based on an operation of a user.
2. Related Art
Recently, navigation devices that perform vehicle travel guidance so that a driver can reach a desired destination easily are often installed in vehicles. Here, a navigation device is a device which is capable of detecting a current position of a host vehicle using a GPS receiver or the like, acquiring map data corresponding to the current position from a recording medium such as a DVD-ROM or an HDD, or through a network, and displaying the acquired map data on a liquid crystal monitor. The navigation device is also provided with a route search function that, when the desired destination is input, searches for an optimum route from the host vehicle position to the destination. The navigation device then displays the guidance route on a display screen and reliably guides the user to the desired destination by providing guidance by voice in situations such as when the host vehicle approaches an intersection. In recent years, mobile telephones, personal digital assistants (PDAs), personal computers and the like often have functions similar to the navigation device described above.
Here, in order to learn facilities located around the vehicle and the road shape through the navigation device and the like mentioned above, it is important that a scale (control value) of a map displayed on a display device is set to an appropriate scale. In view of this, Japanese Patent Application Publication No. JP-A-2000-163031 (page 6, FIGS. 6 to 8), for example, describes changing the scale of the map displayed on the display device based on a user operation. As an example, JP-A-2000-163031 describes a control that enlarges the scale of the map displayed on the display device based on two fingers spreading while touching a touch panel, and reducing the scale of the map displayed on the display device based on two fingers coming together while touching the touch panel.